Propeller.



J. H. C. ALEXANDER.

PBOPELLBR.

APPLIoATIoN FILED Ammo, 190e.

Patented Sept. 19, 1911.

EOLVMBIA PLANOGRAPII CU., WASMINU'I'ON. D. C.

UNITED STATES PATENT OFFTCE.

JOHN H. C. ALEXANDER, OF BERKELEY, CALIFORNIA, ASSIGNOR TO ALEXANDER FAN & PROPELLER COMPANY, A CORPORATION OF CALIFORNIA.

PROPELI'ER.

To all whom it may concern.'

Be it known that I, JOHN l-I. C. ALEX- ANDER, a subject of Great Britain, residing at Berkeley, in the county of Alameda and State of California, have invented a new and useful Propeller, of which the following is a specification.

This invention relates to a propeller or fan of the class of devices which perform their functions by rotational movement against the fluid in which they are immersed.

The object of this invention is to provide a device of the character named, of simple and cheap construction and more efficient to perform a certain character of functions than t-he devices of this class heretofore. Fans and propellers having radial blades formed on the lines of helices or modifications thereof as heretofore constructed have one peculiarity in common z-the fluid impelled from their working surface takes a rapidly diverging conical form. Attempts have been made to overcome this defect by the employment of circumferential casings, ribs, flanges and the like. These, however, in many instances are undesirable and relatively costly additions, not economical of motive power. It is desirable in many instances t-o produce by means of a fan or propeller a current of fluid substantially cylindrical in form under conditions in which it is impractical or otherwise undesirable to employ special devices, such as those heretofore referred to, for changing the form of the fluid current created by the rotation of the fan. Conversely a fan blade, which creates when rotated, a conical form of current, is not economical when used as a motor deriving its power from a fluid current, as for eX- ample, a Windmill, and consequently undesirable.

Another object therefore, of the present invention is to provide a. fan or propeller which will overcome the stated difficulties by creating, when rotated, a `substantially cylindrical current and further to accomplish this object Without the aid of special deflectors. I accomplish this object by means of the devices illustrated in the accompanying drawings in Which:-

Figure 1. is an elevation of one half of a two-bladed propeller. Fig. 2. is a diagram showing the construction of the propeller blade and placed relatively to Fig. 1. in the position of the absent half of Fig. 1. Fig. 3.

Specification of Letters Patent.

Application filed August 30, 1906.

Patented Sept. 19, 1911.

Serial No. 332,716.

is a detail showing a rib-member. Fig. 4. is a plan of Fig. 1. Fig. 5. is a plan of one half ofI a propeller or fan formed of members, such as shown in Fig. 3. Fig. 6. is a plan of Fig. 3.

Reference is to be had to the drawings and especially to Figs. 2, 3, 5, to which the description hereinafter particularly refers, from which a clear understanding will be had, which will enable those skilled in the art, to produce fans or propellers in accordance with my invention for the various applications for which such devices are commonly used.

The form of construction shown in the figures mentioned, is selected to illustrate this disclosure, for the reason that besides being peculiarly adapted to bring out clearly the underlying principle, it has the additional practical advantage of being readily taken apart and packed in small compass for transportation.

F ig. 3. is a. view of a unit or rib-inember, consisting of a boss or hub 1, adapted to ft on a shaft and provided with an arm or projection 2, extending radially therefrom. At a suit-able distance from the hub, the arm 2 is bent or deflected, so that the remaining portion of its length 3 forms a tangent to a circle larger than the huh. rlhis is clearly illustrated in Fig. by the dotted continuation of arm 3 and the dotted arc struck from the center of hub 1.

I have applied to certain lines in the diagram Fig. 2, reference characters similar to those designating corresponding parts of the construction in Figs. 4l, 5, and 6.

Referring now to Fig. 5. it will be seen that a number of rod units, such as shown in Fig. 3. are arranged 0n a shaft 4, their hubs touching each other, so that the planes of rotation of the members are parallel to and equi-distant from each other.

Vith reference to a plane at right angles to the plane of rotation of one of the members, the remaining members, of which the drawings show seven, are arranged successively at regularly Varying distances from each other. This is clearly shown in Fig. 2. in which the angular spaces between the members are arranged in the varying proportion which corresponds to the numerical sequence 3 l 5 6 7 8 9. This is clearly indicated by the finer lines in the diagram. The eight members thus arranged and secured upon the shaft 4 form a frame or backing and also, so far as concerns the tangential parts 3 a form or mold to which the web of the vane may be attached and caused to conform. The vane is shown in Fig. 5. at 5, and also in Fig. 2. as the space bounded by t-he inner and outer arc lines and the lower and the uppermost tangential lines 3, 3. This web may be made of any suitable material such as sheet metal, canvas, or any other material conformable to the rods 3. The web may be attached to the supporting rods in any of the ordinary ways, appropriate to the character of the web material used.

The described construct-ion, as illustrated in Figs. 2, 3, 5, 6, is appropriate for windmills, fans, and the like where lightness and portability are desirable features. For heavier and stronger devices in which the knockdown feature is of minor, or of no importance, the device, as shown in Figs. l and 4, may be formed of cast metal as is customary with propellers. In this latter case however the built up construction which has been described will be found a simple and convenient foundation for or means of producing a pattern from which the propeller,

in accordance with my invention, can be cast.

It is obvious from the description, that the angular spacing of the members, are not necessarily variable only, in the numerical sequence herein shown, but may be varied in any other desired ratio, or even spaced uniformly. Y

From ythe description and drawings it will be seen that the operating surface is in the nature of a helix or modified helix developed by a tangent to a circle concentric to Athe hub, traveling around said circle in a helical or modified helical path.

Having thus described my invention, what l claim is A fan or propeller blade having its entire working surface generated by a line tangent to a cylindrical surface concentric with the axis, and parallel to a plane perpendicular to the axis, the line in sweeping the surface of the blade moving so that its point of tangency to the cylindrical surface describes approximately a helix of variable pitch.

JOHN H. C. ALEXANDER. `Witnesses:

W. H. SMYTH, J. E. AINSLEY.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

